Known methods of producing peptides by utilizing genetic engineering techniques include, among others, causing microorganisms such as Escherichia coli and Bacillus subtilis to produce peptides, proteins and the like by utilizing plasmids and causing hosts to viruses to produce peptides, proteins and the like by utilizing viral DNA.
However, these known methods are not entirely satisfactory with respect to the stability of plasmids, the variety of usable cell species, and production efficiency.
The present inventor previously succeeded in isolating a mouse cell-derived DNA fragment containing an autonomously replicating sequence (ARS) and reported that this fragment is an EcoRI-BglII fragment of about 2,500 base pairs (Mol. Cell. Biol., 5, 563-568 (1985)).
The present inventors carried out further investigations into the properties of this ARS fragment and found that the ARS has affinity for the c-myc protein which is the product of the c-myc gene and that the c-myc protein binds with c-myc gene itself and controls expression thereof. Furthermore the inventor found that not only myc protein but also various DNA-binding proteins have affinity for the ARS. This finding made it possible to separate and obtain the ARS from various mammalian cells using the myc protein and the like. The inventor further found that useful peptides, proteins or glycoproteins, among others, can be produced efficiently by utilizing such a mammalian cell-derived autonomously replicating sequence (ARS), and have now completed the present invention.